6h5c said:
Ray its the dc offset on the output.
It was 22mV and now 2mV
All my regs and the star earth @ the output socket go to that little pcb near the switch and then ground.
I was checking all my reg voltages to see if everything was ok and just happened to check o/p mV. I was suprised by how low it was in stop mode.
Also with the cd in stop mode and the amp on full the output noise is a lot lower indeed
Hello marantz specialists!
I'm interested in fitting my own regulators, especially for my (hopefully) soon to arrive clock. After seeing so many pictures of rowemeister's cd-player i'm also interested in fitting seperate powersupplies for the regulator(s). Since I'm actually an interaction designer/software progammer and not an electronics engineer, what are the dangers of fitting separate supplies? (like for instance creating groundloops or dangers of connecting either the grounds or supply rails together)
And the second question: i've been looking for different regulators to feed the electronics, however I'm not able to find a nice suitable sollution, PSSR and/or output impedance seem to be able to cause trouble... What regulators do you recommend? Any diy regulators among them? Rowemeister seems to be a big fan of the audiocom's invisus and Qpower regulators, but these are not exactly cheap, so any hints and tips would be greatly appreciated!
Regards,
Jacco.
I'm interested in fitting my own regulators, especially for my (hopefully) soon to arrive clock. After seeing so many pictures of rowemeister's cd-player i'm also interested in fitting seperate powersupplies for the regulator(s). Since I'm actually an interaction designer/software progammer and not an electronics engineer, what are the dangers of fitting separate supplies? (like for instance creating groundloops or dangers of connecting either the grounds or supply rails together)
And the second question: i've been looking for different regulators to feed the electronics, however I'm not able to find a nice suitable sollution, PSSR and/or output impedance seem to be able to cause trouble... What regulators do you recommend? Any diy regulators among them? Rowemeister seems to be a big fan of the audiocom's invisus and Qpower regulators, but these are not exactly cheap, so any hints and tips would be greatly appreciated!
Regards,
Jacco.
Dr.Gone said:
Hi Jacco
Yes I like the Audiocom regs, especially from ebay
To start with all my regs and psu were grounded to the ground plane on the top of the pcb. And I had no ground loop problems (or no worse than original configuration).
Now all the regs are sorted I have wired all the grounds to the star point near the mains switch. I got better bass and less output offset voltage.
When you wire in these regs you remove resistors and links off the pcb that would normally connect all rails together.
Has an easy test (just to see whats what etc) I would use 3x 7805 (cheap 5v regs) and power the DAC DECODER to its digital and analogue voltage inputs (refer to mine or Rays mod list for references). Take the voltage from the +20v rail for now, you will be suprised by the improvement from such a small and cheap mod.
You can always upgrade this mod to better caps and regs for even better results.
One thing I will say is 3x 7805 to dac and decoder is better than one good 5v reg that supplies all the pcb, I have tried this and seperate voltage rails everywere wins everytime
rowemeister said:
Hi Jacco
Yes I like the Audiocom regs, especially from ebay
To start with all my regs and psu were grounded to the ground plane on the top of the pcb. And I had no ground loop problems (or no worse than original configuration).
Now all the regs are sorted I have wired all the grounds to the star point near the mains switch. I got better bass and less output offset voltage.
When you wire in these regs you remove resistors and links off the pcb that would normally connect all rails together.
Has an easy test (just to see whats what etc) I would use 3x 7805 (cheap 5v regs) and power the DAC DECODER to its digital and analogue voltage inputs (refer to mine or Rays mod list for references). Take the voltage from the +20v rail for now, you will be suprised by the improvement from such a small and cheap mod.
You can always upgrade this mod to better caps and regs for even better results.
One thing I will say is 3x 7805 to dac and decoder is better than one good 5v reg that supplies all the pcb, I have tried this and seperate voltage rails everywere wins everytime
7805's
take the gound pin and earth to star point
away from cap interferance.
allan
ps or use 317's and grd the adjust resistor the same
rowemeister said:
One thing I will say is 3x 7805 to dac and decoder is better than one good 5v reg that supplies all the pcb, I have tried this and seperate voltage rails everywere wins everytime
This is what Marantz did in later players eg CD6000
I think everyone on this forum is of the opinion that the original psu idea, of all stages being fed from one supply, is the main limitation on performance.
1. Change the psu to separate supplies.
2. Change the clock
3. Change the audio output
Andy
poynton said:
Yep agree.
Although in the 63SE above I replaced standard 50ppm crystal with a custom made 5ppm accuracy and 5ppm cal crystal. I changed the layout under pcb to shorten paths and used silver mica and X7R decoupling cap. It was sooo much better than original crystal.
I would say if for arguments sake the audiocom clocks performance is 100% this 5ppm crystal was 80% with the original crystal being 0%.
Thank you all for the replies, I've just spend a few minutes studying my marantz and the pictures by rowemeister.
Am I correct in assuming the regulator board in the pictures above actually has 3 regulators onboard? And the phrase 'Change the psu to separate supplies.' can also mean installing separate regulators?
Regards,
Jacco
Am I correct in assuming the regulator board in the pictures above actually has 3 regulators onboard? And the phrase 'Change the psu to separate supplies.' can also mean installing separate regulators?
Regards,
Jacco
rowemeister said:
In a previous link i posted, ALW tested the different reg's (317, 7805's)
the best way he found was to take the adjust or grd pin of the reg to a separate earth away from digital or noisey grd.
If grd reference varies a few mV's, so will the output.
I also tested this on a couple of simple reg's i breadboard.
Have to admit ALW is right,
with adjust,grd pin separate, noise on the reg's output reduced a lot,
0.1mV per division on scope, i can hardly see anything.(LM317)
probably under 100uV's
allan
ps I need a better scope
awpagan said:
In a previous link i posted, ALW tested the different reg's (317, 7805's)
the best way he found was to take the adjust or grd pin of the reg to a separate earth away from digital or noisey grd.
If grd reference varies a few mV's, so will the output.
I also tested this on a couple of simple reg's i breadboard.
Have to admit ALW is right,
with adjust,grd pin separate, noise on the reg's output reduced a lot,
0.1mV per division on scope, i can hardly see anything.(LM317)
probably under 100uV's
allan
ps I need a better scope
I can't measure any noise on my audiocom regs (with my psu's)using a 150Mhz scope
The different grounds having mV differences makes sense, especially now with me bringing all my grounds to one spot and the output offset mV is now a low 2mV with no muting.
rowemeister said:
I can't measure any noise on my audiocom regs (with my psu's)using a 150Mhz scope
The different grounds having mV differences makes sense, especially now with me bringing all my grounds to one spot and the output offset mV is now a low 2mV with no muting.
the reg's are referenced to grd
also any noise on grd shows on the output of the reg
the reg's are just LM317's, now with shunt outs.
bit cheaper than audiocom reg's, and somewhat simpler
allan
ps dc offset.............. hmmm
also dc out of dac
I need to think about it
Just a brief update (been busy of late)
The other night I added 3 more 5V regulators to the decoder and HF amp.
Just this mod has improved the clarity of the signal. Percussion is so tight at the moment.
I now have six, 3 feeding the DAC, 2 feeding the decoder and the HF amp.
I'm slowly replacing all the 5v rails.
Been thinking about a discrete equivalent to Ray's tubestage. Just need to order the parts. Looking forward to the outcome.
Cheers,
Phil
The other night I added 3 more 5V regulators to the decoder and HF amp.
Just this mod has improved the clarity of the signal. Percussion is so tight at the moment.
I now have six, 3 feeding the DAC, 2 feeding the decoder and the HF amp.
I'm slowly replacing all the 5v rails.
Been thinking about a discrete equivalent to Ray's tubestage. Just need to order the parts. Looking forward to the outcome.
Cheers,
Phil
Oh yes! It makes a huge benefit! And I'm only using 7805s for now!
How many do 5v regs you have again? I have 7 so far(if you include the original one on board).
For me, I can essentially see just the regs to do, then the coax mod and the output stage. I've upgraded the reservoir caps for the HF and RF stages, but I think I'll leave modding all the HF/RF signal path resistors and caps till later to see how much of a difference it makes. Beyond that(and the blue LEDs
) I wonder if there's a lot more to do electronically - other than improving the regulators.Brent, are you stuck for more things to do to yours?
Cheers,
Phil